Post: "Builds with no index.html file"

Minimal changelog post announcing readthedocs/readthedocs.org#1800

Currently, we are logging this projects, but on August 1st we will be failing
builds that do not generate an `index.html` on the output's directory.

builds-without-index.rst

@@ -0,0 +1,27 @@
+.. post:: July 20, 2023
+   :tags: builders
+   :author: Manuel
+   :location: BCN
+   :category: Changelog
+
+Builds with no ``index.html`` at its output's directory are deprecated
+======================================================================
+
+Historically, Read the Docs has created an auto-generated ``index.html`` file with minimal instructions about how to setup the project correctly
+for those builds that weren't outputting this file.
+This auto-generated file has confused more users than helped them.
+Mainly, because the behavior on Read the Docs was different from the behavior on their local environment.
+
+Due to this, we decided to stop creating the ``index.html`` file automatically.
+Besides, we will check for an ``index.html`` file at the end of the build,
+and fail it with a clear message of the problem if there is no ``index.html`` file in the ``$READTHEDOCS_OUTPUT/html`` directory.
+This will help users to immediately understand what's the problem and how to solve it.
+
+Builds from projects that are not generating an ``index.html`` file **will start to fail on August 1st at ~9AM PST**, after our regular deploy.
+Make sure your project is properly configured and it's creating an ``index.html`` file before that date to avoid unexpected behaviors.
+
+We recommend you following our :doc:`tutorial <readthedocs:tutorial>` to set up your project correctly.
+
+Please, `contact us`_ and let us know any inconvenient you may have with this change.
+
+.. _contact us: mailto:[email protected]